Effect of solvent on crystallization and polymorphic transformation of L-Histidine

Name: Neeranuch Punmalee

LCSH: Burapha University.Chemical Engineering

LCSH: Solvents

LCSH: Crystallization

LCSH: Histidine

Abstract: Antisolvent crystallization is commonly used to study the effect of solvents to the behaviors of the polymorphic crystallization and transformation. Antisolvents can affect the product of crystallization and may promote the crystallization of specific polymorph. In this study, L-histidine (L-his) was used as a model substance. Acetonitrile, acetone, and methanol were used as antisolvents, and water was used as a solvent. The solubility and the behaviors of the antisolvent crystallization and the solution-meadiated polymorphic transformation (SMPT) were studied. The induction time for antisolvent crystallization and the nucleation rate of the metastable form B were also measured. The solubility of polymorph B of L-his decreased with increasing volume fraction of antisolvent and increased with increasing temperature. Induction time decreased with higher supersaturation and antisolvent volume fraction, indicating that the nucleation rate of L-his in antisolvent crystallization increases with higher supersaturation, and antisolvent volume fraction. At all temperature studied, pure polymorph B of L-his was obtained at higher antisolvent volume fraction (XV ≥ 0.7) and supersaturation while a mixture of polymorphs A and B were obtained at lower antisolvent volume fraction and supersaturation. Transformation times depend on the fraction of form A that obtained at the initial stage of crystallization. The transformation rate of the metastable polymorph B into the stable polymorph A at lower antisolvent volume fraction is faster than at higher antisolvent volume fraction. Measured nucleation rates of polymorph B indicate that the mechanism of nucleation is the heterogeneous nucleation. The lower nucleation rate indicates the shorter transformation time.

Burapha University. Library

Address: CHONBURI

Email: buulibrary@buu.ac.th

Name: Lek Wantha

Role: Principal advisor

Name: Adrian Evan Flood

Role: Co-advisor

Created: 2018

Modified: 2020-03-20

Issued: 2020-03-20

วิทยานิพนธ์/Thesis

application/pdf

CallNumber: Th 541.3482 Ne381E

eng

DegreeName: Master of Engineering

Level: Master's Degree

Descipline: Chemical Engineering

Grantor: Burapha University

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